"Omikron: The Nomad Soul (Simply The Nomad Soul in Europe) is a Windows 9x and Dreamcast 3D adventure game developed by Quantic Dream and published in 1999 by Eidos Interactive. It was released on November 1, 1999 for PC and on June 22, 2000 for Dreamcast. A PlayStation and PlayStation 2 version was planned but was cancelled."

The Nomad Soul is set in a futuristic city known as Omikron, which is a densely populated metropolis on the world of Phaenon, the second planet of the star Rad'an. At the start of the game, players are asked by an Omikronian police officer named Kay'l 669 to leave their dimension and enter Omikron within his body (thereby breaking the fourth wall). After doing so, players continue with the investigation of serial killings that Kay'l and his partner Den were originally working on, attempting to pick up where Kay'l was apparently stopped from investigating. The city of Omikron exists beneath an enormous crystal dome, which was constructed to protect against the ice age that Phaenon entered into after its sun's extinction. The city is split into different sectors: Anekbah, Qalisar, Jaunpur, Jahangir and Lahoreh. Because it is forbidden for the inhabitants to leave their respective sectors, each area has developed uniquely, which is reflected by the diverging lifestyles and architecture. Common to all Omikronians, however, is the heavily oppressive and controlling government, which is run by a supercomputer called Ix.